Investigation of force transients during transverse and vortex gust encounters

This paper studies and compares the effects of transverse and vortex gust encounters. A sine-squared transverse gust was physically created in a water-filled towing tank via a free jet, while a vortex gust was created in a water channel by placing a gust generator plate that undergoes a clockwise half-rotation upstream of the test model. Force and flow field measurements were acquired in both cases. It was found that the gust encounter results in large force transients that follow similar trends during both the transverse and vortex gust encounters. In both cases, unsteady forcing was found to have dependency on time varying effective angle of attack. In order to mitigate the gust effects on lift, different pitching maneuvers were investigated and it has been found that forces produced by a pitching motion can dominate the force produced in a gust encounter.